[rescue] SPARCstation 1 boot woes

[Dave McGuire]

On 11/5/25 15:16, Mouse via rescue wrote:
>>> It does, though, have an intact C10112.
> 
>>> It's marked
> 
>>> 	3 3 6
>>> 	1 6 #
> 
>>> Also, I'd need to know whether the band marks the negative or
>>> positive end of the cap.
> 
> I *was* able to determine this by measuring the non-exploded ELC's
> C10112.
> 
>>> Anyone with enough experience with surface-mount caps to know?
> 
>> It's 33uF, 16V.
> 
> Good.  That's about what I'd expect for a power filtering cap.
> 
>> As for the polarization, I need more information.  Is it a
>> cylindrical aluminum electrolytic, and is it a black ink or paint
>> band?  Assuming yes, the band should mark the negative terminal.
> 
> It's yellow/orange plastic, a rectangular parallelepiped with solder
> pads on the bottom ends, and the band is printed in the same ink as the
> markings I quoted above (it looks like orange somewhat darker than the
> body, perhaps low-hiding red or black ink).  Measuring the ends of
> C10112 on the non-exploded board, I see, as referred to one of the
> middle two pins on an unsed "Molex" disk power connector:
> 
> - Banded end: 12.15V
> - Unbanded end: 0.058V
> 
> from which I perform the masterful deduction that the band marks the +
> end. :-)

   ;)

   That is (was) a tantalum capacitor.  On those, the band marks the 
positive end as you found.  It is also sometimes beveled.

            -Dave


-- 
Dave McGuire, AK4HZ
New Kensington, PA